The aquatic air-breathing insect Notonecta has tracheal cells (cells lining the respiratory passages) that contain hemoglobin. What advantage would this metallo-protein serve in a diving, air-breathing insect?

1. This is wrong. This book says that vertebrates use Hb & arthropods use hemocyanin (Cu-based) as their

respiratory pigment.

2. Hmm… Zee insect obviouzly

‘as trrouble sustaining aerrobic

rezpiracion in zee wadairr.

3. This insect

must be an

endotherm with a

high BMR & high O2 demand.

4. I think maybe

the insect

stores O2 in this way.

Gas Gas ExchangExchang

e ine in AnimalsAnimalsDescribe the 4 functional processes involved in most animal respiration.

Compare to gas exchange in plants.

Respiratory OrgansRespiratory Organs

Identify each type of respiratory adaptation, and relate to lifestyle.

Compare (if applicable) ventilation, gas exchange at the respiratory organ, transport of gases, and gas exchange at the tissues.

Challenges of Gas Exchange Challenges of Gas Exchange related to Environmentrelated to Environment

Air vs. Water:Air vs. Water:• 20X more oxygen in air than in water 20X more oxygen in air than in water

(at the same temp.)(at the same temp.)

• Diffusion of gas molecules is more Diffusion of gas molecules is more rapid in airrapid in air

• Air is less viscous than waterAir is less viscous than water– ventilation (air) requires 1/10 the energy ventilation (air) requires 1/10 the energy

of water breathingof water breathing

DiversitDiversity in gillsy in gills

•Describe the dual function of gills in bivalves and polychaetes.

•Two of these animals utilize structures for body movement in gas exchange as well. Describe.

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Gill Structure in FishGill Structure in Fish

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If fish gills are so efficient at gas exchange, why can’t most fish survive out of water?

Gill Ventilation in FishGill Ventilation in Fish

Discuss the negative pressure component in gill ventilation. Discuss the positive pressure component of gill ventilation.

In order to have bulk flow of water over

the respiratory surface, what

must be created?

Countercurrent Mechanism Countercurrent Mechanism forfor

Gas Exchange Gas Exchange

Draw a similar picture showing blood flow and water flow in the same direction. How would oxygen diffusion change?

Nearly 80% of the O2 is removed from the

water as it passes over the gills.

Is this more or less efficient than gas exchange at the lungs? Why ?

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Tracheal System in InsectsTracheal System in Insects

Each cell has a nearly direct meansof gas exchange via the tracheal system (2-4 spiracles on the thorax, 6-8 on abdomen).

What is the advantage of such a system for a small, fast animal?Do insects have respiratory pigments in their hemolymph? Significance?

p. 984

(May serve as storage reserve)

The abdomen in large, active insects like grasshoppers, is used like a bellows to force air out of tracheae with contraction of skeletal muscles.

What happens when these muscles relax?

The experiment illustrated (first performed by the insect physiologist Gottfried Fraenkel) shows that there is a one-way flow of air through the grasshopper. The liquid seals at either end of the tubing move to the right as air enters the first four pairs of spiracles in the thorax and is discharged through the last six pairs in the abdomen.

How is this different from ventilation in mammals? How does it compare to ventilation in birds? Explain.

Liquid seal Liquid seal

(air) (air)

Rubber diaphragm

Mechanics of Mechanics of Respiration:Respiration:positivepositive pressure pressure breathingbreathing

Do amphibians have completely separate pulmonary and systemic circulatory systems?

What other organ(s) may be used in respiration?

Ventilation in BirdsVentilation in Birds

Compare the size and complexity of the respiratory system in birds and amphibians (previous slide), and explain any differences.

Compare the direction of airflow in birds and mammals. What does this imply regarding the pressure gradients at the transport epithelium?

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Mammalian Respiratory Mammalian Respiratory SystemSystem

p. 985

Mechanics of Respiration:Mechanics of Respiration:negativenegative pressure breathing pressure breathing

How do the serous membranes that cover the surfaces of the lungs and line the thoracic cavity facilitate breathing?

p. 986

Gas Gas Exchange at Exchange at LungsLungs

Four factors affect the rate of gas diffusion across a selectively permeable barrier:

1. Solubility of the gas in the membrane

2. Thickness of the membrane

3. _____________________

4. _____________________

The Function of The Function of HemoglobinHemoglobin

Hemoglobin is the only respiratory pigment in vertebrates, but it is a common respiratory pigment among invertebrates as well.

Hemocyanin, a blue copper-containing protein, carries oxygen in crustaceans and most mollusks, within hemolymph. Describe the respiratory organs in these animals.

Would you expect insects (tracheal system) to have a respiratory pigment in their hemolymph? Explain.

Hemoglobin Dissociation Hemoglobin Dissociation Curves Curves

•How is the function of Hb similar to that of enzymes?•Under what conditions does Hb act as a strong acid…as a weaker acid?

Transport Transport of of Carbon Carbon DioxideDioxide

Carbonic anhydrase catalyzes the chemical reaction in both directions. Explain how this is possible…

What “drives” the diffusion of bicarbonate out of RBCs?

Is there a “potential” problem associated with the loss of HCO3

- ?(pun intended )

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